1. Field of the Invention
The present invention relates to veterinary care devices, and particularly to an anesthesia induction chamber for small animals. The chamber may also be used for the administration of a nebulizer to animals with respiratory problems, for the administration of oxygen to animals in a diabetic coma, as an incubator, or generally for the administration of any form of inhalation therapy for small animals.
2. Description of Related Art
In the practice of veterinary medicine, it is sometimes necessary to administer anesthesia to small animals, such as dogs, cats, birds, guinea pigs, rabbits and the like. The two most common modes of administering anesthesia are by injection or by inhalation. A problem which is frequently encountered in attempting to inject the animal by syringe, in intubating the patient, or in placing an inhalation mask over the animal""s mouth is that sick animals are often fractious and occasionally hostile. Consequently, it can be difficult to keep the animal still or immobile while administering the anesthetic.
The present invention provides a substantially enclosed chamber into which small animals requiring anesthesia may be transferred from, e.g., a Hav-A-Hart cage, and sedated so that conventional means for anesthesia maybe employed. The chamber includes substantially gas impermeable walls, an inlet port for the administration of gases, a vent port, a plurality of partition walls, and at least one hinged door. Besides the administration of anesthesia, the chamber is also useful in any situation in which the administration of oxygen or fluids vaporized by a humidifier or nebulizer is desired, such as treatment with humidified oxygen or medications for dilating or clearing the airways. Various patents have been proposed to perform similar functions or which have similar structural elements to the anesthesia induction chamber of the present invention. U.S. Pat. No. 399,609, issued Oct. 13, 1998 to Allen et al., shows a Veterinary Isolation Cage mounted on four legs with a front door having a transparent panel. A pipe exits the top wall of the cage, and a compartment is shown on the bottom of the cage with a second pipe exiting the compartment.
U.S. Pat. No. 275,969, issued Apr. 17, 1889 to T. F. Woodside, describes a wire crate for fowls having a partition wall whose position may be adjusted by an extensible bar engaging a bail attached to the frame of the partition wall. U.S. Pat. No. 3,885,523, issued May 27, 1975 to B. A. Coleman, teaches an enclosed litter box for cats having a partition wall separating a bottom tray into a toilet area and a raised area with a screen floor adjacent the entrance of the box.
U.S. Pat. No. 4,367,696, issued Jan. 11, 1983 to D. P. Hamana, discloses a cat management chamber having fixed side walls, end walls, and a bottom wall. The chamber has a horizontally disposed partition wall forming the top wall of the chamber. The vertical position of the partition wall is adjustable by means of a U-shaped locking pin which extends through holes in one of the side walls and into sleeves on the partition wall. The partition wall has holes for the administration of fluids, and an end wall has a nipple for the administration of anesthesia.
U.S. Pat. No. 4,788,934, issued Dec. 6, 1988 to J. A. Fetter, describes a pet enclosure attached to the exterior wall of a house with a nylon tunnel between a swinging pet door defined in the house door and the entrance of the pet enclosure. U.S. Pat. No. 5,010,845, issued Apr. 30, 1991 to Azpurua et al., shows a reptile cage with a thermostat, infrared light, humidifier, and a divider wall separating areas of the cage. The divider wall hangs from the top edges of the side walls and does not extend entirely to the floor of the cage.
U.S. Pat. No. 4,941,431, issued Jul. 17, 1990 to F. G. Anderson, teaches a system for killing laboratory animals, the animals being placed in an imperforate cage with a wire mesh cover. A device including a cover larger than the cage cover is placed over the cage, a gasket sealing the junction of the device and the cage cover. The device has a quick connect gas inlet fitting and two restricted exhaust ports. A CO2 cylinder with a pressure regulator and a timer valve to deliver a predetermined volume of gas are connected to the quick connect fitting.
United Kingdom Patent No. 2,276,088, published Sep. 21, 1994, discloses an isolator for laboratory animals. When it is desired to introduce items into the isolator, the items are placed into a storage bin below the floor of the isolator. Access to the interior of the isolator is gained through a glove and sleeve in the front wall of the isolator. The door to the storage bin may then be opened and the items brought into the isolator.
A number of patents describe improvements for high density cages for laboratory animals, particular for the delivery of water and air while maintaining environmental separation of the cages to prevent the spread of bacteria and other pathogens between cages. Exemplary patents include: U.S. Pat. No. 4,480,587, issued Nov. 6, 1984 (filter cap for filtering air); U.S. Pat. No. 4,690,100, issued Sep. 1, 1987 (ventilation system with air ducted into the cages); U.S. Pat. No. 4,699,088, issued Oct. 13, 1987 (water manifold for providing water from common source); U.S. Pat. No. 5,190,879, issued Mar. 2, 1993 to Wolfe, et al. (cages with ultra thin membranes permeable to gases but impermeable to microorganisms); U.S. Pat. No. 5,865,144, issued Feb. 2, 1999 to M. Semenuk (cages with laminated air flow through a perforated bottom); and United Kingdom Patent No. 1,179,551, published Jan. 28, 1970 (air flow system through a cabinet employing multiple filters).
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.
An anesthesia induction chamber for small animals has an enclosed chamber defined by a bottom wall, a pair of opposing side walls, a front end wall, a rear door mounted on a hinge, and a top cover attached to a side wall by an elongated piano hinge. The walls, rear door and top cover are impermeable to gases. The front. end wall has a gas inlet port to which a gas source, such as an anesthesia machine, may be attached. The rear door includes a vent port which is adapted to receive a scavenger or other device for removing carbon dioxide or other gaseous waste from the chamber. The chamber has a first partition wall disposed to slide through one of the side walls adjacent the rear door so that a small animal may enter the chamber through the open rear door and subsequently be confined in the chamber by sliding the first partition wall closed. A second partition wall may be inserted to reduce the size of the chamber. After the animal is sedated, the top cover may be unlatched in order to remove the animal from the chamber and continue anesthesia through conventional routes of administration.
Accordingly, it is a principal object of the invention to provide an anesthesia induction chamber for sedating fractious small animals in order to render the animal more amenable to the administration of anesthesia by conventional routes.
It is another object of the invention to provide a substantially air-tight chamber which small animals may be induced to enter for treatment by inhalation of gases or vaporized medications.
It is a further object of the invention to provide an anesthesia induction chamber for small animals in which a fractious or hostile small animal may be confined after voluntarily entering the chamber by a slidable partition wall which encloses the animal in an air-tight chamber.
Still another object of the invention is to provide an anesthesia induction chamber in which the size of the chamber may be adjusted to suit the size of the animal by insertion of a partition wall into the chamber.
It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.